My Shimano polymer coated rear gear cable went today, frayed in the shifter. A mere 5,000km of use. I was getting well over 10,000km from the earlier PTFE coated cables.

Another problem is that the polymer coating separates from the cable and gunks up the outer cable and bottom bracket cable guide. When removing the gear cable, I found it was also jamming in the rear derailleur outer cable (short section from the chainstay cable stop to rear derailleur) due to the gunk.

koshari wrote:Is this what i have to look forward to with internally routed cables?

My bike with the broken rear derailleur cable is externally routed. I have the same cables/groupset on another bike which is internally routed and the front shifting is nowhere near as good compared to the externally routed bike. There's a lot more friction in the internally routed cables. I'm nearing 5,000km with that bike so we'll see if the rear derailleur cable breaks soon.

ALL stainless steel gear cables will break inside the shifter, coated or uncoated, Shimano, SRAM, Campag levers. Stainless steel work hardens and becomes brittle with repeated stress; the drum inside the shifter head is a stress point with the cable repeatedly wrapping and unwrapping around it. Excess friction, such as from scruffy cable coating further along the cable route will add to the stress in the shifter, reducing cable life.

For the record I also dislike the polymer coating; Shimano's PTFE-coated cables are among the best around.

I really don't know the "Biggie" about internal routed cables, really how many watts are saved.

i recently bought an italian external routed cable bike with campy chorus. Most accurate up and down change i have experienced, doesn't miss a beat. I really have to say, why the hype about electronic?

I stopped using Polymer cables a while ago. Likewise, not happy with the cost and barely 5000km lifespan, and the fluffy gunge on an 11 speed.However, the last PTFE cable on an older 10 speed system only just made it to 5000km's. An earlier one made it to 7000km.My LBS has been using SRAM plain stainless, 1.1mm cables (Shimano are 1.2mm) with good results, they claim.Much, much cheaper than PTFE or Polymer I'm trying them out at the moment on a 10 speed and an 11 speed bike. Both are ridden frequently.I can't feel any difference in cable friction and ease of gear change on the rear between Shimano or Sram.I don't know about the new cable's lifespan nor their effectiveness on the front derailleur yet, only fitted to rear.5000km cable replacement has been part of my maintenance routine for some time now.

Tim wrote:My LBS has been using SRAM plain stainless, 1.1mm cables (Shimano are 1.2mm) with good results, they claim.Much, much cheaper than PTFE or Polymer I'm trying them out at the moment on a 10 speed and an 11 speed bike. Both are ridden frequently.I can't feel any difference in cable friction and ease of gear change on the rear between Shimano or Sram.

1/10 of a millimetre makes stuff-all difference. When you work on the things daily, you can feel the difference between coated & uncoated cables, especially with Shimano's 2nd-gen 10-sp. (first with hidden cables) shifters, which are not the smoothest cable routing. 11-sp. are a lot better.

For reference, SRAM's coated cables are just as bad as Shimano's polymer cables.

I'm not doubting that side by side treated cables slide better than untreated but I can live with any extra slight drag. I don't notice much difference. 7900 and 9000 systems work beautifully regardless IMO. I actually prefer the heavier but smoother action of the 7900 shift. The 9000's change so easily they feel lightweight and cheap (I wish they were). It's a personal tactile thing but the 9000 feels less precise, although I know they aren't.I think the real test of the SRAM cables will be on the more heavily loaded front derailleur/s when the time eventually comes.

i recently bought an italian external routed cable bike with campy chorus. Most accurate up and down change i have experienced, doesn't miss a beat.

You might be missing the distinction between internal/external routing through the frame & hidden/exposed cable routing into the shifter. There's not really that much difference between internal & external frame routing, but the difference between hidden (under tape) and exposed (classic Shimano side-entry) routing is significant, with the exposed cabling giving a very light & slick action thanks to its much more direct entry into the shifter. The milliwatts saved by the aero cabling are probably spent on the extra effort required to shift the levers.

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